Multiple transcriptional variants and RNA editing in C18orf1, a novel gene with LDLRA and transmembrane domains on 18p11.2.
C18orf1 is a novel brain-expressed transcript, mapping to 18p11.2. Upon further characterization, we found multiple and differentially expressed transcriptional variants. C18orf1 alpha 1, an 8.5-kb transcript, was predicted to code for a 306-amino-acid protein and a 7.1-kb 3'-untranslated region (UTR). This variant was encoded by at least six exons. Alternative transcripts included alpha 2, identical to alpha 1 but missing 18 residues, and N-terminal-truncated variants termed beta 1 and beta 2. A motif search suggested the presence of a transmembrane domain in both alpha and beta and a low-density lipoprotein receptor class A (LDLRA) domain in the alpha-specific N-terminal. In LDLR, LDLRA has been shown to be involved in binding Ca2+ and LDL, raising the possibility that C18orf1 might bind Ca2+ and an unknown ligand. We also present evidence of RNA editing in the 5'-UTR of beta 2, the first demonstration of this phenomenon in 5'-UTR.
Yoshikawa
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Unit on Gene Mapping and Expression, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA.
Sanders
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Esterling
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Detera-Wadleigh
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D000328:Adult; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D001483:Base Sequence; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics*; D003001:Cloning, Molecular; D005091:Exons; D005333:Fetus; D006801:Humans; D007223:Infant; D007438:Introns; D008565:Membrane Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D017393:RNA Editing / Q000235:genetics*; D011973:Receptors, LDL / Q000235:genetics*; D014158:Transcription, Genetic
C111334:LDLRAD4 protein, human; D008565:Membrane Proteins; D011973:Receptors, LDL